And tonight our ongoing series "real money" how to get real cash in your pocket today. The average american will spend 750 on the holidays so many will try to bring them down by spending hours in black friday lines but we asked sharyn alfonsi to find now ways to save and found one family some real money. Reporter: The perillos have their hands full. Parker, cameron, and baby sawyer. There isn't a lot of time for holiday shopping. Are you dreading it? Anything we can do to avoid bringing all three kids to the mall. Reporter: So we brought help to them. I'm joanna. Nice to meet you. Reporter: Joanna stern is abc tech editor. She showed us how you can outsmart stores, using technology to get great deals. On the perillos' christmas list -- a flat screen tv and digital camera. We were surprised to learn prices online fluctuate from hour to hour. Watch this sony camera. The price dropped three times, from 179 to 168 to 129, $50 in just 12 hours, so when should you pull the trigger and buy? Tip number one -- arm yourself with apps. So we're off to the store. Our target, target. There we see a digital camera we were looking out and pull out our decide app. It scans the barcode, searching through thousands of pieces of information to tell us whether we should buy it now or wait and get a better price. So we will not buy a camera today. It says wait. But what bout this samsung tv on sale? It says buy, so sarah does. On the toy aisle, we spot bouncing tigger. It's at the top of the girl's list. That is going to make you crazy. Definitely will make us all crazy. Reporter: It was $39.99 at target, marked down to $28.99. Tip number two -- click to compare. Using another app called red laser, we scan the bar code and find it cheaper. Target will match competitors' online pricing this year, so we get it for $21. And laser in on other great deals. And if you're shopping online and don't like the price, tip number three -- just walk away. If you put something in your cart and you walk away from it, it's kind of like playing hard to get. They'll send you an e-mail saying, "actually, we noticed you had this in your cart. Here's a 10% discount. Reporter: To trick the computer, you may even need to put in your credit card number in, but don't use it. It's not even about just clicking on it we have to go to the last stop before placing the order. Reporter: And the discounts start coming. Dad hides the gifts we picked up and we count up the savings. 390. That's real money! Don't worry. We made sure the girls wouldn't be watching so we wouldn't ruin their surprises. Often an item is more expensive in the store than on that same store's website. For example, one toy we is saw was $39, 21 -- excuse me, $39 in the store and $21 at target.Com. If you find that lower price, you can finally get it. If you walk away the computer will lure you back? Absolutely. It is watching you but you really have to go all the way to the very end, put your credit card number in there and then back out. Boy, that is really something. Sharyn alfonsi, thanks very much.

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